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/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "common/libs/utils/users.h"
#include <grp.h>
#include <pwd.h>
#include <sys/types.h>
#include <unistd.h>
#include <cerrno>
#include <cstring>
#include <mutex>
#include <ostream>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include "common/libs/utils/contains.h"
#include "common/libs/utils/result.h"
namespace cuttlefish {
namespace {
std::vector<gid_t> GetSuplementaryGroups() {
int num_groups = getgroups(0, nullptr);
if (num_groups < 0) {
LOG(ERROR) << "Unable to get number of supplementary groups: "
<< std::strerror(errno);
return {};
}
std::vector<gid_t> groups(num_groups + 1);
int retval = getgroups(groups.size(), groups.data());
if (retval < 0) {
LOG(ERROR) << "Error obtaining list of supplementary groups (list size: "
<< groups.size() << "): " << std::strerror(errno);
return {};
}
return groups;
}
} // namespace
gid_t GroupIdFromName(const std::string& group_name) {
struct group grp{};
struct group* grp_p{};
std::vector<char> buffer(100);
int result = 0;
while(true) {
result = getgrnam_r(group_name.c_str(), &grp, buffer.data(), buffer.size(),
&grp_p);
if (result != ERANGE) {
break;
}
buffer.resize(2*buffer.size());
}
if (result == 0) {
if (grp_p != nullptr) {
return grp.gr_gid;
} else {
// Caller may be checking with non-existent group name
return -1;
}
} else {
LOG(ERROR) << "Unable to get group id for group " << group_name << ": "
<< std::strerror(result);
return -1;
}
}
bool InGroup(const std::string& group) {
auto gid = GroupIdFromName(group);
if (gid == static_cast<gid_t>(-1)) {
return false;
}
if (gid == getegid()) {
return true;
}
auto groups = GetSuplementaryGroups();
return Contains(groups, gid);
}
Result<std::string> SystemWideUserHome() {
auto uid = getuid();
// getpwuid() is not thread-safe, so we need a lock across all calls
static std::mutex getpwuid_mutex;
std::string home_dir;
{
std::lock_guard<std::mutex> lock(getpwuid_mutex);
const auto entry = getpwuid(uid);
if (entry) {
home_dir = entry->pw_dir;
}
endpwent();
if (home_dir.empty()) {
return CF_ERRNO("Failed to find the home directory using " << uid);
}
}
std::string home_realpath;
if (!android::base::Realpath(home_dir, &home_realpath)) {
return CF_ERRNO("Failed to convert " << home_dir << " to its Realpath");
}
return home_realpath;
}
Result<std::string> CurrentUserName() {
char buf[LOGIN_NAME_MAX + 1];
CF_EXPECT(getlogin_r(buf, sizeof(buf)) == 0, strerror(errno));
return std::string(buf);
}
} // namespace cuttlefish
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